I get this. My point is that the only reason the first part is in Baldur's Gate is because well... it's Baldur's Gate. I feel like if we started in Elturel, making at least some connection to the city, and the people in it, got sent somewhere to do a quest (maybe a ruin where the cult of the dead three or a demonic cult was doing nasty stuff, and we discovered the vanthapurs were behind it) and in the way back we see Elturel falling, the stakes would be higher from the start, and Elturel would mean something personal to the players from the start. They could then go to Baldur's gate after the Vanthapurs, but as written, I felt like I didn't really care about Elturel until latter.